NB: I'm not really posting this for my regular readership but so that this information is available on the internet should someone one day come looking for it.
Nearly two years ago I had a Mirena IUD inserted. Within days of the insertion I developed a uterine infection that caused such severe pain that the Mirena had to be removed after three weeks. The pain resulted in me developing a condition known as central sensitisation. Whilst I had the infection, nerves that normally send other kinds of signals had been commandeered to send pain signals in order to convey to my brain the severerity of the situation. Once the infection was eliminated, these nerves didn't return to their normal functions as they should have and instead continue to send pain signals. This means that, even though I no longer have an infection, I continue to live with significant pain (although that pain is now reasonably well controlled and I am hopeful that it will eventually be eliminated altogether).
I am sharing this story as I believe that my severe chronic fatigue syndrome made an infection following the Mirena insertion a near-certainty. It also seems that the resultant central sensitisation was much more likely to occur in a person with CFS than in a healthy person. I in no way blame my GP for not realising the risks involved in giving me an IUD, but I wanted to put the story on the internet in the hope that other women with CFS would be aware of these possibilities!
Likelihood of infection
As mentioned above, I have very severe CFS/ME. For the past nine years I have had around 15% of the energy I had before I became ill. I am only able to be out of bed for a total of three hours per day; I use a walker to walk within the house and a wheelchair for any trips outside. My muscles are thus extremely deconditioned. It is this that both I and my gynaecologist now believe made a uterine infection almost inevitable once I had had the IUD inserted. Once the (tiny!) weight of the IUD was added to the weight of my uterus itself, my deconditioned pelvic muscles were too weak to continue holding my uterus in its proper place. The Mirena thus bore down on my cervix such that it was pushed very close to the opening of my vagina. At this point infection became inevitable: the strings attached to the Mirena, whilst only 3cm long, were from time to time pushed right out of my vagina to regions where they would have come in contact with bacteria. These bacteria then travelled up the strings into my uterus where they multiplied and caused me such severe pain that several times I thought I might pass out.
Likelihood of central sensitisation
I am much less confident that my central sensitisation was a consequence of my CFS but it does seem that this underlying condition may have put me at higher risk of developing such a condition.
According to Dr. Ros Vallings' report from this year's "Invest in ME" conference in the UK, people with CFS have abnormal pain processing systems. In particular, Professor Maria Fitzgerald's paper apparently noted:
So it seems that there is something abnormal in the way people with CFS process pain signals.In CFS/ME there is altered CNS processing. Fibromyalgia (FM) patients perceive greater intensity and greater temporal summation. Sensations increase in magnitude, and the CNS winds up more and more. There is alteration of endogenous pain control. FM patients lack diffuse noxious inhibitory control. Normally there is ability to inhibit pain (endogenous opioids). There is altered cortical pain processing in CFS/ME. Numerous areas of the cortex are involved. There is activation of the limbic system (anterior insular-based ganglia and cingulated cortex). The CNS is acting very differently.
In addition, Professor James Baraniuk is reported to have made the following observations about fibromyalgia patients:
I don't really understand what he is saying beyond that he mentions something about central sensitisation occuring in fibromyalgia patients. As he was speaking at a chronic fatigue syndrome conference (not a fibromyalgia one) I presume he means that similar things are also observed in people with CFS, although there is no indication in Dr. Vallings' notes that he actually said as much.There was increased sensitivity to deep pressure in FM. There was also increased sensitivity of proprioceptive and stretch receptors on nerves innervating the joint capsules, tendons etc. There maybe loss of the anti-nociceptive system, and loss of norepinephrine release, which normally regulates responses, and initiates autonomic responses. It is as if “the light is on but no-one is home”, and the brain is in a default mode pathway.He looked at pain dolorimetry – pressure-induced thresholds, and did frequency analyses. Central sensitization starts in the periphery – there maybe peripheral sensitisation such as by hay fever. Spinal sensitization leads to hyperalgesia and allodynia.
These snippets make me wonder if central sensitisation following severe pain (as described in Dr. Woolf's paper linked to above) is more likely to occur in someone with CFS as our pain processing systems are, apparently, already not working properly.
If your CFS isn't as severe as mine then I suspect that the above scenario is unlikely to happen to you. If, however, you are very inactive and your muscles don't always hold your innards in place like they should then please be aware that it is a possibility!
PS, if you'd like to know more about any of this, please put a question in the comments or email me.